JP2009080346A - Optical cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical cable in which optical elements are pulled out easily and an optical fiber network is constructed smoothly. <P>SOLUTION: The optical cable 1 comprises a plurality of optical elements 2, in which a coating layer 7 is provided on the outer circumference of a coated optical fiber 5, are bundled in parallel without being twisted. Thus, each optical element 2 is drawn out of the optical cable 1, without having to unwreathe the bundle and is pulled out smoothly. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical cable suitable for use in constructing an optical fiber network.

  There is an optical fiber network called FTTH (Fiber To The Home) that guides an optical fiber to an individual user (house-to-house). When constructing this optical fiber network, an optical element is formed by covering the optical fiber with a covering layer together with a tension member, an optical cable in which a plurality of optical elements are bundled is laid, and the optical element is connected to each user from the main line. It will be distributed as far as possible. Since this optical cable is handled such as being transported while being wound around a drum, the optical elements are bundled in a twisted state in order to absorb the difference in diameter between the inner and outer circumferences when wound around the drum. (For example, refer to Patent Document 1).

JP 2001-215375 A

When an optical cable is formed by twisting a plurality of optical elements as described above, the frictional resistance increases exponentially with respect to the number of twists even if the optical element is pulled out from the branch point from the main line, so that the drawing is not performed. Have difficulty. Therefore, it is necessary to untwist each optical element when it is pulled out from the optical cable toward each user. For example, when the drawing length of the optical element from the main line to the user is 10 m, if the twist pitch is 600 mm, the twist must be unwound about 17 times.
If the position is close to the terminal of the optical element, the work of untwisting is not so difficult, but if it is far from the terminal, for example, in the case of the above example, the 10 m optical element must be rotated about 17 times with respect to the main line. First, the work of untwisting becomes very difficult work.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical cable in which an optical element can be easily pulled out and an optical fiber network can be constructed smoothly.

  The optical cable of the present invention capable of solving the above-described problems is characterized in that a plurality of optical elements each provided with a coating layer on the outer periphery of the optical fiber core wire are bundled in parallel without being twisted. .

  In the optical cable according to the present invention, it is preferable that a plurality of the optical elements are bundled by a bind line.

  Moreover, the optical cable which concerns on this invention WHEREIN: It is preferable that the winding pitch of the said bind wire is 10 times or more of the diameter which bundled the said several optical element.

  Moreover, in the optical cable according to the present invention, it is preferable that the plurality of optical elements are covered and bundled with a loose tube type jacket.

  In the optical cable according to the present invention, it is preferable that the plurality of optical elements are bundled by a plurality of bind wires having different winding strengths or winding pitches.

  Moreover, in the optical cable according to the present invention, it is preferable that the tensile strength wire is arranged at the center and a plurality of the optical elements are bundled around the tensile strength line.

  In the optical cable according to the present invention, it is preferable that an air layer filled with air is provided between the tensile wire and the plurality of optical elements.

  Moreover, the optical cable which concerns on this invention WHEREIN: It is preferable that the said several optical element is bundled in the state which provided the line length difference.

  In the optical cable according to the present invention, it is preferable that the plurality of optical elements are bundled in a non-close-packed state having a gap therebetween.

  In the optical cable according to the present invention, it is preferable that at least a part of the covering layer is made of any one of high-density polyethylene, polypropylene, and fluorine resin.

  Moreover, in the optical cable according to the present invention, it is preferable that an inclusion made of any of high-density polyethylene, polypropylene, and fluorine resin is provided between the plurality of optical elements.

  In the optical cable according to the present invention, it is preferable that the arrangement of the optical elements is divided by the inclusions.

  In the optical cable according to the present invention, it is preferable that the optical elements are coupled in parallel in units of two or more.

  Moreover, it is preferable that the optical cable according to the present invention is packaged in an 8-letter bundle.

  In the optical cable of the present invention, since a plurality of optical elements are bundled in parallel without being twisted, it is not necessary to untwist when each optical element is pulled out. Therefore, each optical element can be easily pulled out and the optical fiber network can be constructed smoothly.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
1 is a perspective view of an optical cable, FIG. 2 is a cross-sectional view of the optical element, FIGS. 3 and 4 are cross-sectional views of other examples of the optical element, FIG. 5 is a perspective view illustrating a winding pitch of the bind wire, and FIG. FIG. 7 is a front view for explaining the laying of the optical cable, FIG. 8 is a perspective view for explaining the excitation direction when the optical element is pulled out, and FIG. 9 is a sectional view of another example of the optical element.

  As shown in FIG. 1, the optical cable 1 is a cable in which optical elements such as a drop cable, an indoor cable, and an optical cord are used for applications such as FTTH. A plurality of long optical elements 2 laid up to each user (door-to-house) are arranged in a straight state without being twisted, and are bundled in a bundle with a bind wire 3.

  As shown in FIG. 2, the optical element 2 includes a pair of tension members 6 arranged in parallel with an optical fiber core 5 in which a glass fiber made of a core and a clad is provided with a coating such as an ultraviolet curable resin. The coating layer 7 is provided on the outer periphery of these.

  The covering layer 7 has a substantially rectangular shape whose cross section is long in the arrangement direction of the pair of tension members 6. Further, the covering layer 7 is formed with an R chamfer 8 in a square shape, and a pair of concave portions 9 having a V-shaped cross section with the optical fiber core wire 5 interposed therebetween. The pair of recesses 9 is for enhancing the ease of cutting the coating layer 7 when the optical fiber core wire 5 is led out. In addition, as shown in FIG. 3, it is good also as a shape which makes both R chamfering 8 of a short side into one continuous circular arc, and forms the one side of the recessed part 9 in the edge part of this circular arc. Moreover, as shown in FIG. 4, it is good also as a shape which does not form a recessed part in the coating layer 7. FIG.

  The covering layer of the conventional indoor cable is formed of, for example, low density polyethylene (LDPE) or linear low density polyethylene (L-LDPE). In the present invention, the covering layer 7 is made of high density polyethylene (HDPE), polypropylene. (PP) and low friction resin such as fluorine resin. Or the coating layer 7 is formed from the synthetic resin containing a lubricating material.

  The bind wire 3 is formed by coating a relatively soft metal wire, such as an iron wire, that easily retains the shape when bent, with a resin, and is wound around a plurality of optical elements 2 at a predetermined winding pitch. . As shown in FIG. 5, the winding pitch L of the bind line 3 is set to 10 times or more the diameter of the assembly core 4 in which a plurality of optical elements 2 are bundled.

  And the said optical cable 1 is good to accommodate in the accommodation box 11 before use, as shown in FIG. Since the optical cable 1 is integrated in a bundle of 8 characters, there is no difference in line length between the optical elements 2, so that the optical element 2 can be prevented from being scattered before and after the optical cable 1 is unwound from the storage box 11.

  When laying the optical cable 1 in an existing apartment house S such as an apartment, for example, the optical cable 1 in a state of being bundled in a bundle of 8 in the storage box 11 is drawn out from the lead-out hole 12 and shown in FIG. Then, the optical cable 1 is laid in a straight line in the vertical direction, and an arbitrary optical element 2 is pulled out from the optical cable 1 and distributed.

  For example, when there are two dwellings 14 on each floor and a common meter box 15 is provided for these dwellings 14, any two optical elements 2 are pulled out from the optical cable 1 and installed to the same meter box 15. Then, one optical element 2 is distributed from the meter box 15 to each dwelling unit 14.

  At this time, as shown in FIG. 8, the drawing resistance can be further reduced by pulling out the optional optical element 2 while vibrating the assembly core 4 manually or by machine. Further, at this time, it is preferable to lay the trunk line with a margin as shown in FIG. 7 so that the optical cable 1 can be distributed and distributed to the uppermost dwelling units.

  According to the above-described embodiment, each optical element 2 is pulled out from the optical cable 1 in a state where a plurality of optical elements 2 are bundled in parallel without being twisted. The trunk line is laid, and then the optional optical element 2 is pulled out from the optical cable 1 and distributed. As described above, since a plurality of optical elements 2 are bundled without being twisted, when each optical element 2 is pulled out, twisting does not occur without untwisting, so that it can be easily pulled out.

  Thereby, it is possible to facilitate the laying of the optical cable 1 to an existing apartment house S such as a condominium as well as a detached house, and a smooth construction of the optical fiber network can be realized.

  Further, if the winding pitch of the bind wire 3 is sufficiently long, for example, if it is made an order of magnitude (10 times) larger than the diameter of the assembly core 4 in which a plurality of optical elements 2 are bundled, the binding force will not be strengthened, so The power is kept low. Therefore, the optical element 2 can be easily pulled out even when the bind wire 3 is wound.

  Moreover, since the coating layer 7 consists of either high density polyethylene, a polypropylene, a fluorine resin, or a synthetic resin containing a lubricant, mutual contact resistance can be reduced. Therefore, the optical element 2 can be pulled out more easily. In particular, if a high-density synthetic resin is used, since it is resistant to damage, the amount of resin in the coating layer 7 can be reduced to reduce the cross-sectional area of the optical element 2, thereby increasing the mounting density of the optical cable 1. .

  Further, since the R chamfer 8 is formed on the coating layer 7 of the optical element 2, the optical elements 2 do not come into surface contact with each other even in a bundled state, and the contact resistance can be reduced. Therefore, the optical element 2 can be pulled out more easily. In this case, as shown in FIG. 9, the same effect can be obtained even if the covering layer 7 has a circular cross section.

  Further, when an arbitrary optical element 2 is pulled out while vibrating the optical cable 1, the optical element 2 can be pulled out more easily.

  In the optical cable 1, a plurality of optical elements 2 are arranged side by side without being twisted and are bundled by a bind wire 3. Can be absorbed, and dispersion of the optical element 2 due to a difference in line length can be prevented. In order to reduce the frictional resistance between the optical elements 2 without removing the figure 8, a difference in the line length between the optical elements 2 may be set to about 1% so that the optical elements 2 can be appropriately dispersed. In this case, however, the packing becomes large because it is necessary to bundle the optical cable 1 with a diameter of 100 times or more the outer diameter of the optical cable 1 or to wind it around a drum. Therefore, in the FTTH and the like, particularly in a narrow work space such as a building or a condominium, there is a great advantage of performing 8-letter packaging in which the optical element 2 is not easily scattered even if it is wound around several times the outer diameter of the cable.

  In the above embodiment, the case where the optical cable 1 is installed in an existing apartment house S such as an apartment has been described as an example. However, the present invention is also applicable to installation in each detached house.

Further, the embodiment described above can be modified as follows.
FIG. 10 is a perspective view of a modification of the optical cable. As shown in FIG. 10, the bind wire 3a is wound around the plurality of optical elements 2 together with the above-described bind wire 3 at a winding pitch longer than this. That is, a plurality of optical elements 2 are bundled by a plurality of bind lines 3 and 3a having different winding pitches.

  According to this configuration, after the trunk line is laid in a state of being tightly bundled by the plurality of bind lines 3 and 3a, the long-pitch bind line 3a is not cut, and only the short-pitch bind line 3 is cut and bundled. After the weakening, any optical element 2 can be pulled out and distributed. Therefore, it is possible to prevent the optical cable 1 from being scattered by the bind wire 3a having a large winding pitch.

  The plurality of optical elements 2 may be bundled by a plurality of bind lines having different winding strengths, instead of being bundled by the plurality of bind lines 3 and 3a having different winding pitches. In this case, after the optical cable 1 is laid, the binding wire having a relatively low winding strength is not cut, the binding wire having a strong winding strength is cut, and an arbitrary optical element 2 is pulled out and distributed. .

  FIG. 11 is a cross-sectional view of a modification of the optical cable. As shown in FIG. 11, a plurality of untwisted optical elements 2 may be covered and bundled with a loose tube-type outer casing 17 having a gap with respect to the plurality of optical elements 2 instead of the binding wire. . In this case, it is preferable that at least the inner side of the jacket 17 is made of high-density polyethylene, polypropylene, fluorine-based resin, or a synthetic resin containing a lubricant.

  If configured in this way, the line length difference between the optical elements 2 will be properly aligned in the outer casing 17, so that it is not necessary to accumulate in a bundle of eight letters to make it snare free. It is also acceptable to wind it around. Further, since the outer cover 17 is present, at least the appearance is not affected by the difference in the line length of the plurality of optical elements 2, and the lateral pressure resistance of the optical cable 1 can be improved. In this case, the outer sheath 17 of the optical cable 1 provided with the trunk line is cut at an appropriate position, and the optical element 2 is pulled out and distributed.

  FIG. 12 is a perspective view of a modification of the optical cable. As shown in FIG. 12, a tension member 19, which is a long tensile wire, is disposed at a position that is approximately the center of a plurality of optical elements 2 that are not twisted. That is, the tension cable 19 is arranged in the center, and the optical cable 1 in which a plurality of optical elements 2 are bundled around the tension member 19 is used.

  In this case, the optical cable 1 in which the tension members 19 are arranged in the center of the plurality of optical elements 2 is laid, and then the tension member 19 is pulled out from the optical cable 1 and then sequentially pulled out from any optical element 2. Will be distributed. When the tension member 19 is pulled out, the porosity increases and the contact resistance between the optical elements 2 can be reduced. Therefore, the optical element 2 can be pulled out more easily. In particular, the tension member 19 can be easily pulled out from the inner optical element 2 in which a space is formed.

  FIG. 13 is a cross-sectional view of a modification of the optical cable. As shown in FIG. 13, a tension member 19 that is a long tensile wire is disposed at a substantially central position of a plurality of optical elements 2 that are not twisted, and the tension member 19 and a plurality of light beams are arranged. Between the element 2, a tubular air layer forming member 22 that forms an air layer 21 filled with air is provided.

The air layer forming member 22 is made of a thin film resin that is filled with air and can be damaged using a tool or the like. In this case, the optical cable 1 is laid and the air layer 21 is then evacuated by making a hole in a portion of the air layer forming member 22 facing the end of the optical cable 1. Thereby, the porosity increases and the contact resistance between the optical elements 2 can be reduced. Then, an arbitrary optical element 2 is pulled out and distributed. Therefore, the optical element 2 can be pulled out more easily. In particular, it is easy to pull out the inner optical element 2 from the space formed at the position of the air layer 21.
The optical element 2 may be pulled out after the tension member 19 that has been easily pulled out is pulled out after the air inside the air layer forming member 22 is released.

FIG. 14 is a cross-sectional view of the optical cable wound around the drum, and FIG. 15 is a front view of the optical cable unwound from the drum.
As shown in FIG. 14, an optical cable 1 composed of a plurality of untwisted optical elements 2 is wound around the outer periphery of a body portion 26 between a pair of flange portions 25 (only one is shown) of the drum 24, thereby Thus, the optical element 2 wound around the drum 24 and the optical element 2 wound around the drum 24 on the outer peripheral side are bundled in a state where a line length difference is intentionally provided.

  When the drum 24 has a trunk diameter of 100 times the cable outer diameter and the optical cable 1 is drawn out from the drum 24 and laid as a trunk line, the line length difference between the optical elements 2 is reduced to within 1%. As shown in FIG. The void ratio between the optical elements 2 increases moderately due to the difference in length. Therefore, the contact resistance between the optical elements 2 can be reduced, and the optical element 2 can be pulled out more easily.

  FIG. 16 is a cross-sectional view of a modification of the optical cable. As shown in FIG. 16, a plurality of untwisted optical elements 2 are bound in a non-close-packed state having an appropriate gap between each other, not in a close-packed state where the outer diameter of the assembly core 4 is minimized. Bundle with line 3. Thus, if the optical elements 2 having irregular cross sections are bundled without being aligned, the contact resistance between the optical elements 2 can be reduced, and the optical elements 2 can be pulled out more easily. The broken line D1 indicates the outer diameter line of the assembly core 4 in the non-closed state, and the broken line D2 indicates the outer diameter line of the assembly core 4 in the close-packed state.

  FIG. 17 is a perspective view of a modification of the optical cable. As shown in FIG. 17, a plurality of low-friction long inclusions 28 made of any one of high-density polyethylene, polypropylene, and fluororesin are provided between a plurality of untwisted optical elements 2. If comprised in this way, the contact resistance of the optical element 2 can be reduced with the inclusions 28, and the optical element 2 can be pulled out more easily by pulling it out from what contacts the inclusions 28.

  FIG. 18 is a cross-sectional view of a modification of the optical cable. As shown in FIG. 18, when a plurality of low-friction long inclusions 30 made of any of high-density polyethylene, polypropylene, and fluorine-based resin are provided between a plurality of optical elements 2, these interpositions are provided. The arrangement of the optical element 2 is divided by the object 30. That is, the inclusion 30 has a plurality of radial partition portions 31, and the individual optical elements 2 are disposed between the adjacent partition portions 31. If comprised in this way, the contact resistance of the divided optical element 2 can be reduced by the inclusion 31 and the entanglement between the optical elements 2 can be reduced, and the optical element 2 can be pulled out more easily.

  FIG. 19 is a cross-sectional view of a modification of the optical cable. As shown in FIG. 7, when there are two dwellings 14 on each floor and a common meter box 15 is provided for these dwelling units 14, two optical elements 2 are connected to each other as shown in FIG. 19. The optical cable 1 is formed by bundling a plurality of optical element coupled optical elements 32 that are coupled together without being twisted.

  If comprised in this way, the one optical element coupling body 32 is pulled out from this optical cable 1 laid by the trunk line, this one optical element coupling body 32 is distributed to the corresponding meter box 15, and this optical element is distributed. The combined body 32 can be separated into two optical elements 2, and one optical element 2 can be installed in each dwelling unit 14.

  Therefore, the drawing work time can be reduced, and the plurality of optical elements 2 can be prevented from being entangled with each other at the time of distribution, and the distribution to the meter box 15 can be facilitated. Note that the optical elements 2 are not limited to two, but can be connected in parallel in units of two or more according to the installation situation.

  FIG. 20 is a front view of a modified example of the laying of the optical cable. As shown in FIG. 20, first, the optical cable 1 is folded over the apartment house S in a folded state, then the optical element 2 at an arbitrary position is cut from the optical cable 1, and both the cut optical elements 2 are pulled out. Distributed. In other words, the upper cut body 2a after the cut optical element 2 is cut out from the optical cable 1 and distributed to the upper floor, and the lower cut body 2b after the cut optical element 2 is cut out from the optical cable 1. Pull out and distribute to lower floors.

  By laying in this way, the optical element 2 is used as a set on the upper floor and the lower floor, the number of optical elements 2 can be reduced, and the optical element 2 can be used effectively. In this case, when the optical cable 1 is folded, the folded portion is lifted, or the end portion of the optical cable 1 is lifted by a pulley, and the optical cable 1 is folded and lowered at the position of the pulley, whereby the optical cable 1 can be laid in a folded state.

  Necessary to pull out the optical element by 15m for an example in which 32 optical fibers having a cross-sectional outer dimension of 2 × 3 mm are bundled without binding and are bundled with a binding wire, and with a twist of 600 mm. The pull-out force was measured. The coating layers were all L-LDPE. The results are shown in [Table 1].

  As can be seen from [Table 1], when a twist of 600 mm pitch is added to the optical element, the pulling force of the optical element exceeds 20 kg, whereas in the case where no twist is added, the pulling force is significantly 5 kg. We were able to reduce to.

  Further, with respect to an example in which the coating layer of the optical element not added with the twist was HDPE, an example in which LDPE was used, and an example in which L-LDPE was used, the pulling force required to pull out the optical element by 15 m was measured. The results are shown in [Table 2].

  As can be seen from [Table 2], when the covering layer is LDPE, the pulling force of the optical element exceeds 20 kg, and when the covering layer is L-LDPE, the pulling force is 5 kg. Thus, in the example in which the coating layer was HDPE, the pulling force could be greatly reduced to 300 g.

  Also, the smaller the binding wire winding pitch, the higher the effect of bundling the optical elements. However, tightening the optical element bundle at a short pitch increases the pulling force of the optical element, and the binding wire winding pitch is too long. And the optical elements are easily separated. For this reason, the winding pitch is preferably in the range of 50 mm to 2000 mm, and preferably in the range of 200 mm to 600 mm.

  Each optical element can withstand a tension of about 10 kg, and even if there is a difference in wire length between the optical elements, about 30% of the total allowable tension can be expected as the effective allowable tension of the optical cable. Is not necessary. Also, when the outer cover is applied to improve the lateral pressure resistance of the optical cable, the outer cover does not adhere to the assembly core composed of a plurality of optical elements, and the optical element 2 is pulled out with a force of 20 kg / 15 m or less. It is preferable to use the aforementioned loose tube that extrudes the sheath into a loose shape (tubular shape).

It is a perspective view which shows the example of embodiment of the optical cable which concerns on this invention. It is sectional drawing of an optical element. It is sectional drawing of another example of an optical element. It is sectional drawing of another example of an optical element. It is a perspective view explaining the winding pitch of a bind line. It is a perspective view of an optical cable and a storage box. It is a front view which shows the installation of an optical cable. It is a perspective view explaining the vibration direction at the time of optical element extraction. It is sectional drawing of another example of an optical element. It is a perspective view of the modification of an optical cable. It is sectional drawing of the modification of an optical cable. It is a perspective view of the modification of an optical cable. It is sectional drawing of the modification of an optical cable. It is sectional drawing of the state which wound the optical cable around the drum. FIG. 14 is a front view of a state where the optical cable of FIG. 13 is unwound from the drum. It is sectional drawing of the modification of an optical cable. It is a perspective view of the modification of an optical cable. It is sectional drawing of the modification of an optical cable. It is sectional drawing of the modification of an optical cable. It is a front view of the modification of laying of an optical cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical cable 2 ... Optical element 3, 3a ... Binding wire 4 ... Assembly core 5 ... Optical fiber core wire 6 ... Tension member 7 ... Covering layer 8 ... R chamfer 11 ... Housing box 14 ... Housing 17 ... Outer casing 19 ... Tension Member (Tensile wire)
21 ... Air layer 24 ... Drum 28, 30 ... Inclusion

Claims (14)

  An optical cable, wherein a plurality of optical elements each provided with a coating layer on an outer periphery of an optical fiber core wire are bundled in parallel without being twisted. The optical cable according to claim 1,
An optical cable characterized in that a plurality of the optical elements are bundled by a bind line. The optical cable according to claim 2,
An optical cable characterized in that a winding pitch of the bind wire is 10 times or more a diameter of a bundle of a plurality of the optical elements. The optical cable according to claim 1,
An optical cable characterized in that a plurality of the optical elements are covered and bundled by a loose tube type jacket. The optical cable according to claim 1 or 2,
An optical cable, wherein the plurality of optical elements are bundled by a plurality of binding wires having different winding strengths or winding pitches. An optical cable according to any one of claims 1 to 5,
An optical cable, wherein a tensile strength line is arranged in the center, and a plurality of the optical elements are bundled around the tensile strength line. The optical cable according to claim 6,
An optical cable, wherein an air layer filled with air is provided between the tensile strength line and the plurality of optical elements. An optical cable according to any one of claims 1 to 7,
An optical cable characterized in that a plurality of the optical elements are bundled in a state where a line length difference is provided. The optical cable according to any one of claims 1 to 8,
An optical cable, wherein a plurality of the optical elements are bundled in a non-close-packed state having a gap therebetween. An optical cable according to any one of claims 1 to 9,
An optical cable, wherein at least a part of the covering layer is made of any one of high density polyethylene, polypropylene, and fluorine resin. The optical cable according to any one of claims 1 to 10,
An optical cable comprising an inclusion made of any one of high density polyethylene, polypropylene, and fluorine resin between the plurality of optical elements. The optical cable according to claim 11,
The optical cable is characterized in that the arrangement of the optical elements is divided by the inclusions. The optical cable according to any one of claims 1 to 12,
An optical cable, wherein the optical elements are connected in parallel in units of two or more. An optical cable according to any one of claims 1 to 13,
An optical cable, wherein the optical cable is packed in a bundle of 8 characters.

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